jcain

unsprung weight AND height AND contact patch, big diff.

Lost In Sync

Tires and rims can make a big difference. If you really want to know jack the trucks up and remove a wheel and weigh them.

Joewee3.5

Take your truck in. I complained about mileage when I first got my truck but after a year and a half I've realized my truck is normal. Yours in the other hand is well below normal. Today from Dallas to shreveport I set the cruise at 85 (10 over speed limit and I never speed but I was testing). To my extreme surprise I got 17.1 mpg for 30 minutes. That's insanely high for my truck especially at that speed. On a trip going south for nearly the same miles and got 17 mpg at 75. So I can go faster east to west but not north to south? Crazy but I'm sure wind or elevation effected it.

matt.s

I've taken it in and the dealer just gives me the run around...tells me to call Ford customer service and complain.

Dude, i'd be the happiest oerson if I could hit 17 going 85! I'm looking at a best case of maybe 14. My dad typically does 21-22 at 70 on long trips. I don't know what's wrong with my truck.

dsg2003mach1

this

I think it would be a worthwhile experiment for the community. Ive been pretty surprised at how little it takes to mess with fuel mileage from head winds/tail winds to very slight inclines over long stretches. A bigger tire its having to turn that also has more contact patch creating more friction is going to change things. I wouldnt have thought it would be THAT much but it would be interesting to know

Joewee3.5

Believe me I was surprised too. I have seen 13 mpg at 80 before. I'm tickled at mileage on the highway lately. It's garbage in town but the highway mpg is up quite a bit.

Mark Miller

What about if you fill both trucks up and trade trucks for a week and check mileage?I have a 2011 F-150 Supercab 4X4 EcoBoost and 3.55 LS rear.I have over 14,000 miles and my lifetime average is 16.9 mpg.I live in Northeast,Ohio so part of that 14,000 miles was cold weather.

Later Mark.

acadianbob

Big, heavy wheels and tires KILL fuel mileage.

CoreyMS

At 70...for at least 30 minutes what does it say?

Twisty

4 wheel drive vs 2 wheel drive. I honestly think that is the real problem plus the tire size makes it a bit worse.
Part of the transfer case gears are always spinning even when in 2 wheel drive.
You have the weight of the case, the front drive shaft, suspension components, plus you have more air resistance as the front sits a bit higher.
A big part of aerodynamics on cars is preventing air from getting under the chassis. If air does get under it is best to have a smooth body pan not great big chunks of hardware hanging down.